Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

S (Solid Earth Sciences) » S-CG Complex & General

[S-CG54] Hard-Rock Drilling: Oman to Oceanic Lithosphere to Island Arc Formation and Beyond

Mon. May 21, 2018 3:30 PM - 5:00 PM A09 (Tokyo Bay Makuhari Hall)

convener:Eiichi TAKAZAWA(Department of Geology, Faculty of Science, Niigata University), Katsuyoshi Michibayashi(Department of Earth and Planetary Sciences, Nagoya University), Peter B Kelemen (共同), Damon A H Teagle (Ocean & Earth Science, National Oceanography Centre Southampton, University of Southampton, SO14-3ZH, Southampton, UK), Chairperson:Michibayashi Katsuyoshi, Abe Natsue(R&D Center for Ocean Drilling Science, JAMSTEC)

4:45 PM - 5:00 PM

[SCG54-16] Advanced Well Logging across Crust-Mantle Transition in Oman

★Invited Papers

*KYAW MOE1, Yasuhiro Yamada1, Saneatsu Saito1, Kazuya Shiraishi1, Adam Wspanialy1, Yoshihiko Tamura1, Eiichi TAKAZAWA2, Oman Drilling Project Phase II Science Party (1.Japan Agency for Marine-Earth Science and Technology, Center for Ocean Drilling Science, 2.Department of Geology, Faculty of Science, Niigata University)

Keywords:Oman Drilling Project, Crust-Mantle Boundary, Well Logging, ICDP

To clarify the mohole discontinuity which was first identified in 1909 as step in the velocity of the seismic wave, it is necessary to drill and sample across crustal-mantle transition and that was original idea of the scientific ocean drilling more than four decades ago. This study is aiming to maximize the understanding on the petrophysical, geophysical, petrological and chemical nature across crustal-mantle transition, and to support in realistic planning for D/V Chikyu drilling and sampling fresh mantle in the future.

Under the International Continental Drilling Program (ICDP) support and guidelines, core samples from the crust-mantle (CM) boundary were taken in the Phase II (Nov., 2017-Jan., 2018). In addition, drilling parameters were monitored and recorded from two CM sites with cooperation from the drilling companies, and most advanced well logging was carried out to the depths where logging tools could reach.

Schlumberger’s wireline logging acquired high-resolution and continuous density-porosity, natural and spectral gamma, resistivity and its images, sonic velosity (P & S waves), and geochemical logs (elements and minerals). Preliminary results of acquired and processed well logging data across crust-mantle transition will be presented and plan for the data integration studies will be discussed. As first ever geophysical site survey taken from one of three offshore Mohole targets recently, potential application of Oman study results in the planning offshore Mohole to Mantle drilling (M2M) will also be introduced.